Archaeological excavations at a site believed to be a temple in Heijo-kyo, Japan, have revealed fragments of what is thought to be a heating therapy tool known as 'Onjaku'. These artifacts, shaped similarly to those previously found in Dazaifu, suggest a fascinating link between ancient Japan and the Korean Peninsula, specifically the Silla kingdom. Experts believe that the heating stones, used to alleviate symptoms by applying heat to affected areas, might have been standardized items imported from Korea.

The site where the stone was unearthed was investigated by a private research organization, the Mongakuji Cultural Property Research Institute, and researchers assert that the newly found stone dates back to the late Nara period to the early Heian period. The artifact measures approximately 11 centimeters in length and width and about 5 centimeters in thickness, originally possessing a thick, oval shape. Although the stone is cracked, its impressive size and the material, a soft stone known as talc, have caught the attention of researchers who highlight that such stones are uncommon in Japan and may indicate foreign origins.

The discovery raises significant questions about the cultural exchanges between Japan and the Korean Peninsula during the Nara period. The resemblance of the artifacts from both Heijo-kyo and Dazaifu could provide insights into the transportation and trade routes of that era, emphasizing the influence of Silla on Japanese culture. As archaeologists continue their investigations, this finding could deepen our understanding of Japan's historical connections with its neighbors and the shared practices in medical treatments of the time.